1. cigarette box
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    30 Oct '06 10:35
    Bare with me if im wrong. Im do not study physics so this is just a 'throw' into the wind.

    According to Einstein e=mc^2
    If this is so, when travelling at the speed of light one thus 'becomes' energy itself. Therefore if you, and the car you are in are energy, does this not mean you cannot physically turn on the headlights?
  2. Standard membergenius
    Wayward Soul
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    30 Oct '06 10:56
    Originally posted by RedDevil4Life
    Bare with me if im wrong. Im do not study physics so this is just a 'throw' into the wind.

    According to Einstein e=mc^2
    If this is so, when travelling at the speed of light one thus 'becomes' energy itself. Therefore if you, and the car you are in are energy, does this not mean you cannot physically turn on the headlights?
    as your speed increases so does your mass. indeed, your mass tends to infinity as your speed tends towards c. so your arm would be too heavy to move. so, no you would not be able to turn on your headlights.

    it is a hypothetical situation though...
  3. Joined
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    30 Oct '06 12:13
    Originally posted by RedDevil4Life
    Bare with me if im wrong. Im do not study physics so this is just a 'throw' into the wind.

    According to Einstein e=mc^2
    If this is so, when travelling at the speed of light one thus 'becomes' energy itself. Therefore if you, and the car you are in are energy, does this not mean you cannot physically turn on the headlights?
    This equation equates mass to energy wheter you are tavelling at the speed of light or not. Mass is a form of energy.
  4. Joined
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    30 Oct '06 15:16
    Originally posted by Ian68
    This case would be different. For you to see reflected light there has to be time for the light waves to travel from the source to the object, and then from the object to your eye. If both you and the light source are moving together at the speed of light then there is not time for this to happen, you will pass objects before the light reflects off them.
    If a light source is travelling at the speed of light, won't the light emitted in the direction of its motion be travelling at twice that speed?
  5. Joined
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    30 Oct '06 15:27
    With regards to the very first question. If you're traveling at the speed of light and you turn on your headlights--there are two ways to answer that question. First, if you had to assume the speed of light (C) and your headlights were on, the answer would be yes because the light that left your lamps prior to your attaining C would be visible since youw ould be behing those beams. If you were traveling at the speed of light and you turned on your lights, you MAY see the beam of lights depending on where your headlights are relative to your position within your vehicle.

    In terms of the second question: If you are traveling at the speed of sound, and turn on your radio, you WILL hear the radio becuase the air in your compartment will carry the sound waves to your ears--even if the compartment was open, you would hearthe sound. YOu will however not hear much of the sound around you since your vehicle, whatever it is creates a vortex in which all sound pushes past you--unless something intersects your path--in which case the sound would carry to your ears.
  6. Joined
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    30 Oct '06 15:38
    Originally posted by henryinma
    With regards to the very first question. If you're traveling at the speed of light and you turn on your headlights--there are two ways to answer that question. First, if you had to assume the speed of light (C) and your headlights were on, the answer would be yes because the light that left your lamps prior to your attaining C would be visible since youw ...[text shortened]... t you--unless something intersects your path--in which case the sound would carry to your ears.
    When a problem starts with "Suppose you travel in the speed of light and..." everything get meaningless. It is impossible to travel in the speed of light, V=C, totally impossible. Any conclusion would be wrong.

    No mathematician would answer any question starting with "Suppose you divide with zero and..." In the same sense it is impossible to divide by zero, any conclusion would be wrong.

    The mathematical reason you cant travel in the speed of light is that you actually have to perform a division by zero.

    But if you can always start a problem with "Suppose you travel with a speed near to that of lights and..." but then you have to take the massive relativistic implications of it. into consideration.
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    30 Oct '06 15:56
    Originally posted by FabianFnas
    When a problem starts with "Suppose you travel in the speed of light and..." everything get meaningless. It is impossible to travel in the speed of light, V=C, totally impossible. Any conclusion would be wrong.

    No mathematician would answer any question starting with "Suppose you divide with zero and..." In the same sense it is impossible to divide by ...[text shortened]... but then you have to take the massive relativistic implications of it. into consideration.
    No, but a mathematician would answer a question starting "suppose you have a rigid light (i.e. weight = zero) rod. Which is just as impossible. But the physical impossibility doesn't stop you answering the question in a useful way which shows you understand the physics of the situation.

    "Suppose you are travelling at the speed of light" is just like that. A thought experiment. You can answer it meaningfully without changing the fact it's a physical impossibility.
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    30 Oct '06 17:04
    Originally posted by mtthw
    "Suppose you are travelling at the speed of light" is just like that. A thought experiment. You can answer it meaningfully without changing the fact it's a physical impossibility.
    But no one knows what's going to happen because it is utterly impossible. My idea is that all mass converts to ice-cream with chocolate flavor.

    Impossible? Well, it is impossible to travel in light speed from the beginning. And I happen to like ice-cream with chocolate flavor.

    If you start with an impossibility, then the result is totally without meaning.
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    30 Oct '06 17:14
    Originally posted by FabianFnas
    But no one knows what's going to happen because it is utterly impossible. My idea is that all mass converts to ice-cream with chocolate flavor.

    Impossible? Well, it is impossible to travel in light speed from the beginning. And I happen to like ice-cream with chocolate flavor.

    If you start with an impossibility, then the result is totally without meaning.
    I disagree. You can demonstrate you understand the physics even with an unrealistic scenario. As a number of people have done in this thread.
  10. Joined
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    30 Oct '06 17:27
    Originally posted by mtthw
    I disagree. You can demonstrate you understand the physics even with an unrealistic scenario. As a number of people have done in this thread.
    But there are no physics involved with a velocity of light with a object with mass. Any attempt of this kind is wrong, as is division by zero.
  11. Joined
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    30 Oct '06 18:30
    Originally posted by FabianFnas
    But there are no physics involved with a velocity of light with a object with mass. Any attempt of this kind is wrong, as is division by zero.
    It doesn't change the real point of the question, though.

    People have answered the question meaningfully, therefore it is possible to answer meaningfully.
  12. Joined
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    30 Oct '06 18:59
    Originally posted by mtthw
    It doesn't change the real point of the question, though.

    People have answered the question meaningfully, therefore it is possible to answer meaningfully.
    So what happen when travelling in light speed? Where is the science in this? How to prove scientifically that you're not turning into ice-cream with chocolate flavor? It simply can't be done. This is no science.
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    30 Oct '06 22:07
    Originally posted by FabianFnas
    So what happen when travelling in light speed? Where is the science in this? How to prove scientifically that you're not turning into ice-cream with chocolate flavor? It simply can't be done. This is no science.
    Do you have a theory of how you turn into ice-cream, that can produce testable results that have been confirmed by experiment? If you do, then the extreme theoretical case of travelling at light speed would be relevant, even if it's not possible.

    The point of the problem is not what happens when a body is accelerated to light speed. The point is what happens if you try to add speeds together at or near light speed. You could frame it in terms of: you have a hypothetical particle moving at light speed (like a photon but different). This particle decays, emitting lower energy particles travelling at light speed relative to the initial particle, in various directions. What would happen?

    Or you can frame the question in terms of cars. The question is made more accessible to people while the principles involved are identical. If you don't get hung up too much about needing an infinite amount of energy to make it happen.
  14. Standard memberAThousandYoung
    or different places
    tinyurl.com/2tp8tyx8
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    30 Oct '06 22:15
    Originally posted by ChessManCLoss
    Then how do u explain lightning?
    Lightning bolts travel at 6.1 x 10^7 m/s, which is slower than the speed of light.

    http://adsabs.harvard.edu/abs/1981JGR....86.5253H
  15. Standard memberAThousandYoung
    or different places
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    30 Oct '06 22:29
    Originally posted by mtthw

    You could frame it in terms of: you have a hypothetical particle moving at light speed (like a photon but different). This particle decays, emitting lower energy particles travelling at light speed relative to the initial particle, in various directions. What would happen?
    Check this out:

    http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/headlights.html
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